Patent Literature 1 describes an inverter apparatus in which a signal from an operation key is input to an inverter control device and the inverter control device creates numerical data and causes a numerical-data display unit to display the numerical data, and creates a blinking pattern and causes any one of a plurality of function indicator lamps to blink. Specifically, when a power supply is turned on, in response to an output from the inverter control device, a function indicator lamp for frequency designation setting is lit and the numerical-data display unit displays numerical data for the frequency command setting. When an operation key of an operation-item switching key is operated, the function indicator lamp for the frequency command setting is extinguished and a function indicator lamp for output frequency monitoring is lit. The numerical-data display unit displays numerical data for the output frequency monitoring instead of the numerical data for the frequency command setting. When an operation key of an operation command key is operated, an alternating-current electric motor rotates. The inverter control device causes the function indicator lamps to sequentially blink and displays a rotating direction to coincide with a rotating direction of the alternating-current electric motor. Consequently, according to Patent Literature 1, the inverter control device lights a function indicator lamp for an operation item, causes the numerical-data display unit to display a numerical value of the operation item and changes and sets the numerical value, causes function indicator lamps for a plurality of operation items to sequentially blink and displays a rotating direction. Therefore, operability of the inverter apparatus is improved and rotation display is clearly shown.